what is frequency...............?

Question

I'm talking about those different radio channels and those bluetooth frequency what exactly are they...Some kind of vibrations ?? I read some where Bluetooth uses 2.45 GHz frequency which was previously UNUSED, means they are something naturally occuring ?? further on what basis radio channel names are determined like FM or what ever....Please explain in simple language ,...

Answer 1

1/T (T= Time Period)

Answer 2

that is electromagnetic radiation



this is generally not something that occurs naturally ...



2.45 GHz means there are 2.45 * 10^3*10^3*10^3 cycles per second





in electronics



10^3 is Kilo

10^6 is mega

10^9 is giga

10^12 is tera





http://en.wikipedia.org/wiki/Gigabyte



good luck..



AM is called AM because of the modulation used not the frequency .. the frequencys were the ones that they could generate a strong enough signal at the time AM broadcasts were first invented...



as technology progressed higher and higher channels or frequencies become available..



In amateur radio ... which has many types of modulation from AM to side band to FM



each different band is allowed to transmit only the allowed type of modulation





for example I think VLF or Very Low frequencies used on submarines were amplitude modulation ... they were used because LONG wave length of radio can penetrate the water..



but long wavelengths means that FREQUENCY modulation would be impractable because in order to get a modulation of 20khz... at something like 100 khz.. 1/5th of the band would be used up





this is just off the top of my head I have been a radio operator in amateur radio for years...





now AM was the frequencies that were long enough to be able to be easily generated by a large commercial setup but also short enough that the bands were not too large... each station has a band width of 10 khz, I think on AM broadcast band





this means that at ... 680 khz.. the frequency will be at least from 675khz to 685 khz



this allows many stations to be put on the dial of a standard radio and the receiver is not to complicated...





from I think its about 500 to 1500 khz is the band for a typical AM Radio



I think the FCC and DOC in usa and canada spread the stations 10 khz apart so that they dont interfere because ... using my 680 example





a station at 680 and a station at 690



the 680 station would use 675 to 685 and the station at 690 would use 685 to 695 see how the lower part of the higher station touches the higher part of the lower station...



that is how they set up the dial..





AM having a bandwidth of only 10khz means its sound is not as good as FM which has I think 20Khz band width





http://en.wikipedia.org/wiki/AM_broadcasting



now FM was at a very High frequency because technology allowed it.. and because of the form of modulation the quality of sound was better because the natural phenomenum of lightning didnt affect FM as much as AM



so it became a desired mode of transmitting signals over radio because of the clarity and high fidelity



the band width being larger 20 khz means the stations had to be at least 20khz apart...



I think that is the standard in american and canadian stations...



after FM the frequencies are named by their frequency or type of radiation



Microwave radiation is a certain frequency...



Gamma radiation is a certain frequency...



or the bands are named by the frequency



like 2.5 GHz band...



10 GHz band



and so on ...



there is no real standard for it just what the FCC or communication body decides to call it...

Answer 3

All of the radio and TV channels use electromagnetic radiation.

It is a form of wave that has energy continuously moving from magnetic to electric and back again.



All waves require two forms of energy to alternate between.



The waves CAN occur naturally in limited conditions. For example as a result of a lightning strike.

But these conditions are rare so we get very little natural interference in our reception.



There are many names but they don't all apply to the same thing.

There is AM for "Amplitude modulated" and "FM" for frequency modulated. But these terms have very little to do with the bands that they are applied to.



To work successfully the FM wave requires more frequency and bandwidth compared to the simple AM system.

So when we set up radio stations using this technology we ALSO chose a different range of frequencies to permit them to transmit on.



Other names are used such as LF ( low frequency) HF ( high frequency)

Short wave ( high frequency)

VHF ( very high freqeuncy) UHF ( ultra high frequency)

microwave ( extremely short wavelength - extremely high frequency)



As these have no physical meaning they only have meaning when you learn the particular legal bands available in specific countries.

Answer 4

Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short-wavelength radio transmissions in the ISM band from 2400–2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security.



Radio frequency (RF) is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals. RF usually refers to electrical rather than mechanical oscillations, although mechanical RF systems do exist.

Answer 5

Frequency is the number of cycles of a wave there is every second. The frequency of a radio wave can be changed and you can match the frequency of the radio broadcaster to receive what the waves carry, those MHz,GHz are just units for measuring frequency. Frequency is measured in Hertz, there are also megahertz(Mhz), GHz and UHF (ultra high frequency)

Answer 6

u have asked what is frequency, so the frequency is one complete change in cycle ie starting from zero(0) then towards positive side above zeroline to again towards zero line and then towards negative side below zeroline and then again coming towards zeroline, and this coplete change in colled one cycle, and measured as cycles per second the number of may be from one to mega, giga, and son, so as the frequecy go to higher level, it produces different charactoristics like radio frequency or microwave etc, there is no such natural frequecy because in nature there many type of frequencies like radio frequency, microwave, freequency modulation(FM), mobile tower frequencies, which r nerer but less in intencity than microwaves so these r harmful to human beings. blutoothe is a simple device working on the pricple of low and limited range frequencies, there are catagories for identifying the radio frequencies, to not get interfere within eachother, to avoid distarbace produced due to electro magnatic waves whic r mostly produced due to sparks produced in petrol engine for ignition,

f/m means frequency modulation, ie the group of frequencies under the shilded frequncies due to which the transmissin is cler and interrerence free the digram may explain more about this.

Answer 7

The rate at which something occurs or is repeated over a particular period of time or in a given sample.

The fact of being frequent or happening often